He isn’t even in Parliament, yet Nigel Farage has emerged as the dominant figure on the political scene in recent months.

The other party leaders are utterly eclipsed by the excitement that he generates.

The surge in support for Ukip can partly be explained by mounting anger at the betrayal of our country by the political class, especially the accelerating loss of our national identity through mass immigration and the dogma of multiculturalism.

Yesterday an opinion poll for the European Parliamentary elections put Ukip on an astonishing 38 per cent, no less than 11 points ahead of Labour and more than double the backing for the Tories.

Farage’s charismatic and forceful personality has played a central part in Ukip’s extraordinary rise.

Without his unique ability to connect with a large section of the public his party would have enjoyed nothing like its present success.

A key element of his appeal is his effectiveness as a communicator, whether on the platform or on television.

Unlike the evasive automatons produced by mainstream parties Farage comes across as humorous, frank, honest and self-deprecating.

He is not afraid of loving his country or indeed of enjoying himself.

His pint of beer and lighted cigarette are the twin symbols of his fight against political correctness.

It is a measure of his growing influence that speculation over his possible candidacy in the forthcoming Newark by-election became the biggest political story of the moment.

This byelection has been triggered by the resignation of the Tory MP for Newark in Nottinghamshire, Patrick Mercer, who was revealed by a journalistic sting operation to have accepted money from lobbyists against all Parliamentary rules.

Yesterday Farage brought all feverish conjecture to an end with his declaration that he would not be running as a Ukip candidate in Newark.

With typical candour he set out a number of reasons for this decision, including the fact that he wished to avoid any distractions from the European elections on May 22 and that he did not want to appear an opportunistic carpet-bagger since he had “no real connections with Newark”.

Furthermore he stressed that Ukip should not be seen as a “one-man” band since his party boasts a number of other impressive politicians, such as the articulate deputy leader Paul Nuttall and Diane James, who performed so creditably in last year’s Eastleigh by-election.

Above all he admitted that it would have been a major setback if he had lost, fearing that a defeat in Newark would have brought the momentum from the European elections to a juddering halt.

Certainly Newark would have been a difficult seat for him to win since the Tory majority at the last election was more than 16,000 and Ukip won only 3.8 per cent of the vote.

There are much more winnable seats for Farage to fight, such as the Isle of Thanet area in Kent where I live.

Not only has Ukip a huge following here, holding most of the municipal seats, but Farage hails from nearby Herne Bay.

So his decision was understandable, even tactically astute.

Yet it is impossible to avoid the feeling that Ukip has missed a golden opportunity to press home its advantage.

If the Tories had lost Newark in the wake of a humiliation at the European polls rebellion would have spread like wildfire through the Tory backbenches and David Cameron’s position might have become untenable.

In politics, like in war and sport, leaders should do what their opponents most fear – and in this case a by-election contest with Farage is what the Conservatives really dreaded.

It is telling that after Farage announced his decision the Tory high command gave a large collective sigh of relief.

Nor should the difficulties of winning Newark be exaggerated.

This is hardly rock-solid Tory territory.

Indeed the seat was actually won by Labour in the 1997 general election.

Furthermore, as a string of by-elections have shown in the past three decades, a 16,000 majority is hardly impregnable.

At Christchurch in 1993 the Tories saw a majority of 23,000 transformed into a Lib Dem majority of 16,400, while at Ribble Valley in 1991 a Lib Dem landslide saw a Tory majority of 19,500 easily overturned.

Labour under Tony Blair’s leadership suffered the same fate, seeing majorities of more than 13,000 wiped out in Brent North in 2003 and Leicester South in 2004.

In politics, like in war and sport, leaders should do what their opponents most fear

It is never easy for a sitting government to defend any seat in a by?election.

There is another interesting echo from the past.

In the early 1980s the fledgling Social Democratic Party was enjoying exactly the kind of upswing that Ukip is experiencing today.

Then in the summer of 1981 a by-election was called in the Labour seat of Warrington.

The SDP’s most popular figure, former Cabinet minister Shirley Williams, came under intense pressure to stand, especially after an opinion poll showed she would win easily.

But she refused on grounds of work and family commitments.

She later called her decision “probably the biggest single mistake of my political life”.

Her career never recovered.

Labour held the seat and the SDP ultimately failed to break the mould of British politics as had once seemed probable.

Farage is not running scared as his critics suggest.

For years he has proved himself a heroic fighter against the political establishment.

But if Ukip fails to make a real breakthrough at Westminster in the coming year he may come to rue his decision on Newark.